🚀 go-pugleaf

        In regard to question 2 about calculating percent error:
I use a force table experiment where the resultant of 3 concurrent forces
should be zero.  The students are asked to find the resultant of any two
of the forces and then compare that value to the remaining force.  They
should be equal and opposite.  You can then compare the difference in
magnitudes to the smaller one or to the average of the two to calculate
percent difference.  Of course the direction may also be off.
        This method has the added value of emphasizing that when the
total of several items is zero, any one of them must be equal and
opposite to the total of all the others.  It's amazing how many students
fail to grasp that concept.

Everett Hinton
Central Community College
Hastings, Nebraska